SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e635d149a30cee1fee2508413d0d78e0a3409d0926c5ec21e2b0aa064843ad99' 
  AND token = '4x0tgZLGHadovqFqE8MzEMfteWpGR5HJ1dd4mG1kcBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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