SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8e04b58c18e06e83ffff25a397e0acce52cce080d72ee56d70fde0edbfd1e7c' 
  AND token = '0NLYz2Czox6fSv8GynRzy+DL77xM0QmjsJKDDhLrhew=' 
  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"
    }
  }
}