SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c85ed69c6176e3ccf53fde42016623e2a0525e8405526affef4f2c3149c79cd' 
  AND token = 'w3VQJzMV1COm1Fhg1LHPk+ucwPilADSR04UfgVIeOFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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