SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03eb96297d11878495a8903ae57a783703d63c81047b5248e799f7aed58d2b7b' 
  AND token = 'jpdlNVOUyE97Z/bPGF36+oSqD3d8mLQNUpf2aLCfNeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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