SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '771aa612e61885c6d9b1226dd0e9ffde4fc94f8af3b689eb8fc47000c34a258c' 
  AND token = 'XRCm6XRMeFrX5/BCKlO/NQRLW/pvaph7as8TqjsKLag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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