SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dfa1658550be6d1393b985f08d508231464f9a6208852643641b5a6a4576358' 
  AND token = 'C7ANUwVyHULneWbqQ7A59FVt7zWDhalyuX44A/vntiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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