SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53e33dd75a8fcd45d094af54fac208d5ea9e684d6c8ebce711df794a93abd96e' 
  AND token = '6ouD1e6AYViDW8rkhzmsxlRiajzwHUSx6pwsg1ClHSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}