SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3f991888481c1f370fe9e94495244e33dca60ed4c170a9fa6309f14db5984b5' 
  AND token = 'MnVtvHC7LjCmuMg0/bMUG/e8dIxW8rDAmluFjD0RKJI=' 
  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"
    }
  }
}