SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67d553180f5861ecf29fa72addb03f8225655746e6e4febadd3accd9d297201c' 
  AND token = 'ph7p5UFhJMgGeOhl1qVhhddsS9ojH2Oq7fkM7kUiDY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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