SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '338c593d000b765a759413a3f24ee33c14093e675551adaa0449beaa1eab0ef9' 
  AND token = 'P4A+Ycu9vJaE+dxzO7iShCNaspJ2w9kwdeX/wtvyqng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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