SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90048e272107cabe6464514128d30592b5def582608b555f1c81de56a79c1ebe' 
  AND token = 'WpQq3fDFSN02UeTY6lGhJ7K3xtn07mWBhfpUIvfqT2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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