SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f6461f31497941c1178cb22d1ceb77539a4a27566f798a4a5dc0e2f278fd8aa' 
  AND token = 'ACC/vwm4temtDJiPETDK2loOtBUVM7ORuK4Xr98PDcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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