SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fa33b28fe53ae465c8dbef540f545a0138047007bf31029d9e7a87525fb8e90' 
  AND token = 'gFjSmXToLevJB1uTryLfbJCZvfaqGcJZ4xIC/EpEuJQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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