SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '57f3dcb04df2958adb6810b2221fa458afcc88f017787b8427ddd99ecf6b9cd2' 
  AND token = 'nrtDEqhFoFo02Bw596vZBetyYpMlLH/czH96l+MYtZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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