SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af47dca4204cfc77b161aee1985b037331e367f24e65319361759d733903c146' 
  AND token = 'ilx2XrRYoJ8S59waVOUinaeoYUcCzr+F5/M0Sdz5+GM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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