SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81115353291ec0ef4a327c7f83bedd72ed36d0981d0aeec6d3aaf78936b80150' 
  AND token = 'mFikNWWFIbsFqZZ1pGxHOCOEK5exqvgG7e5qS+Cr5ws=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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