SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffae70e5cac12319e05ab450ca09624b062394f95126af22c2fa9c1d64881df6' 
  AND token = 'C83FTR/J4zHICqGge4RGKtnGteJ+qSQEaong9XDMtgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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