SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16b1d75807de6c52d35b4bffabd09d1113cad1ce6cc4892d53836269d6ccff8a' 
  AND token = 'juKRgTa1+jm2sFOUExRq5apsE7qs6S9UUYl6Hdn/Mds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00125

JSON explain

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