SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e9d40191a552e463f447be59c110ab57f0681c2c19da59a612e61b55f69f3b3' 
  AND token = 'QXs8SSWu59wf3ZWf51LX/NOagAq4D7phmAeUmCfEuow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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