SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f63c76292c84032b52f3d35e9d9f035effecf7b458289daf9a604aa2df724fbd' 
  AND token = 't+aaRAfb9LXulKA/wkWctpKEfKMzs+WXcNb/CiT+T5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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