SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '52cb4da6bf641b0e03543d1e0dd5dc1be834247a6f0f1d48cf1a0321dea305e6' 
  AND token = 'DUnj8P/iQFK0J+4cgFR8XImVlY0hiHJq5Fx6SQXZ3Kw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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