SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a2745a2672d68070a073a3fd56de67de18ae98fae7b4bccffdc6d0a63fb29d7' 
  AND token = '6eMQ4XBPVM+NNN9nj7I4mZWJhDQyHQpFtAeq1WTq7Zo=' 
  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"
    }
  }
}