SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cacb276d2d169a66be367b57e23b7a406fc88d591ee12241e1a836b6da9d4537' 
  AND token = 'BauJGQik0sdEXgvjWTNr8MN5DTrznjxfXbLVbODFMF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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