SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'afc7e86209207727654304b020d6e1698fe90226ddf5237c9467930b5855b705' 
  AND token = 'gGaVgNzQdOfQv9lrqehZVVQoVB/3jJD+6lEnO1oU+nE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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