SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c53068cd10b64085f6dc3e54da3debc5eed2b38717a061fe40b98b295d1a84a8' 
  AND token = 'HY6gsI3hznuIgDXTtBUpkZgtmt19pRPDgxJ76AqnqxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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