SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a0c22859c13b5189b88571348e7037bf86cd40b3537849872d9265015a657f6' 
  AND token = 'QchvwuvAFcainG4BO6QbsqvjvWsByPaEkZh0OIblLCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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