SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89f4b75a4c96e8c2214a4302f30315f96dddb7de572a4c50e396916cb0f90325' 
  AND token = 'gAwI4LZzr40i3zej+Wghrm1hVroYNNEjCQhXjCJyMcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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