SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6de5a162d298cace27af9ee7b8de9c2a33c3ff44098000593563388b98203290' 
  AND token = 'h/ZzY72IeK/wqiUVBbE2NdFYVwzPE4p/c5pqkoQv7i0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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