SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4172e9822ec069fbe135d55eed6486a233bb5230967e108f42dddf70298c3e4c' 
  AND token = 'Sa8Dygxn5gb/HMMCfDqLyRtbVNz+IgtJP3Ir7kzVQNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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