SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '18fb6a147514c53fb3a5285b71209c30c616bb14eb61038353a6e29cf96faded' 
  AND token = 'UDwK89aXKCZKLaACBsFFleyL+il7SJ3iljtxqQsoR8o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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