SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '684a56b558b1d35586f146a2788dba6ca9ebe8cbb72bb9b6647a014836950adf' 
  AND token = 'BMjJlerj3G4BT1Q7XlxVSJPaY+hDJDlaMPTsRFfOKdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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