SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0fa38b1c75b09b9701f00f86398ee77562b2305973552f04086d88eb264eeb3b' 
  AND token = '1QDxofEI1vg4Dz6EIUybZcVYUjdpPcpHnN7+ukZZZNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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