SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '927cdf9307fe1b8aca9a39a7ea2fc54755649f3eb810f03e24512392d0c47b8c' 
  AND token = '9Hil/cGdYYsllYk2xZvSIHrBvE0qSCB+NTrnzZaLThQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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