SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '19a014d04654c4397daef7cfcf0ba1e79482add395198e202248631e573f2159' 
  AND token = '+0sjKgEef4WrFCmguMeFN4jAhyFECCxIJmQkVc+3LZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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