SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7816553ee21371d0aa6ca7d230ce52c8fdf02797391f9bcb076b38139e25bdf3' 
  AND token = '8uiQQc7DBsyfvnFFQuuYyhC9G2JZ0NODRJVtCoKLuXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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