SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5a6e467b8553566d85c16de24b2b096101cda34288397c6029e0a29f317bf53' 
  AND token = 'jqDAZoNrwAc6Gt5qUfa3OLHqp3xrXop691sQylJ9kyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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