SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd9b11864cf94519f148065585b5d38c5f3a68a260be3a7cd3898678498333309' 
  AND token = 'S4rbu/6wMD+h8EyNtJhQDuNb5DIzFbp7BOK48FZN+GY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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