SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7bd216c244fe2b152a68fbb07d4ccd0683f519d6af2d6d1bea7b5d0e1fcfd5f' 
  AND token = 'CO+O63v0rIlfZwSCnLk8mVL+ZADvBWnzxXJDHsnVZ/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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