SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1648f7e917d929dec768e6e592128b05ab6b9a067960119ec519a320fe2745c5' 
  AND token = 'Qfqoh9ALP+6pHBgzC0UrcDlFMj35dRYJ+wAjORm93Q4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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