SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fe2057a2e1cf6a518a2125f17aa19db7acda7d32a91dbf4751078416da7e931' 
  AND token = 'fz2SjRrLOp6TNUCweBvVwYAAosfT5EdgTBFQvNIely0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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