SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecb711745a69acc074aabedbc290521777c9223861e8943c10e1eb332b385a9a' 
  AND token = 'pRYg+zJkDhCBWu45acJU2NLr/0qUmjfighC+FvWHi8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}