SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8e6f0f9c82b89528707376ce1e209a402904563ed2c0fada125461992b481f25' 
  AND token = '2c/ugY0T6x4LebLP7ljb4Xzk7DIb447WIC2a1TQluAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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