SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e516146954148da278caadb0fd6c40ff16ee539e71296011c133c945e002018' 
  AND token = 'MdKX0071ZX7PjVx8TDXNamFAGOtKajPfJ26qexkROXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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