SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '959b4fed8f5847f44c26d5d346f6f0346d0a056d59fb053fa0b60892bf047954' 
  AND token = 'AJGlsDLKHgJDWUpaKDh4fjvK9fTtf6aLN8YV1BRbJxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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