SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '063c16b1ea15c804eda223f5578d416492359938a65ea2a597458740b4856fcb' 
  AND token = 'PL1VuKFOVL5lhQdF2OeyBBbENMctvU6qUC7MhVcAFD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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