SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '635b312ad03e91eb5010888cfcd2b84468391a718dbb58e7378dbe3fce897663' 
  AND token = 'CB/IrxW9D0BnGN99Zem7t5mOckViDMzphy0lGfIKaGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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