SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaaeb8be4fccaaf320891193bb276f50b14f0f7f775d67ea36a5023af430ed26' 
  AND token = 'C3mwMRV+EzZel7KnHsJxxLaZBGQzf8KzOw8+DqgFTF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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