SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08ceeac74aa9d561f98e0db6c2bda730888154163a3402d2352e6b6fa1d4796b' 
  AND token = 'JLIjcIm7x1jdiwtBP8xHVWQ8cMEzJvwc5snl/e1uo48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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