SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '142ae938fef2c4002f80d4094199e38fcd5005a440e4c22a721b28c7fd6dd938' 
  AND token = 'OLukXCU3gGrgPmVsnApyv1j3atifLP/JKULutaCOM6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}