SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bddda81abaefbec5ca23b851dd49aebb4774652d43a2441069b3fdf7efe048a4' 
  AND token = 'gL7jDC6sbiwqfL6GP13DXonSzsRM3Wkz4ybxHZ2HRj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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