SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6740640b12dffa1fdc63a2fea7842c32f6e654425ba6f962cc7e0b808d6f2cc0' 
  AND token = 'KCNF2vJyYBwZ7qgJu70MNIjYfPmhOUZijWNQN4og5ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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