SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f75f40e1328ee572554e3743b2e6db685b2ea5b18d09abfabc00773c71757771' 
  AND token = 'JNFV9Ywi4X8CfZbc6Yvw3GAAMfMiQKYNey+BHimZQvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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