SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8da1d5e8f46cad3e2a3209edf85cdf157a02a6406c29079a79951d0a95236cd2' 
  AND token = '9HVOw7kIM0elPVYgV7tEoAwydrfxywM7wdz1q4/TtmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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