SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '525fc3a0db066bfe2c6c231f48029ed26673999a808a0881b7253ba2e0da425c' 
  AND token = 'fqttoeH6Igvmbq3x8QbDaciB91P+hOlWl40zdgQSFZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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