SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '785988ad615ef74db0bd23295ac3118872f03c33f8672b2d362e31bda2b883cc' 
  AND token = 'vJ8SyihCjQWUQzb659nK41bmT4OG3wqEDGDhg5AdrFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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