SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7037af7970b86c4c1585961db34773f9a41cb2ebe72832e0cb47028e68bed1fa' 
  AND token = 'JI3q2XTEznfOvrZ4McCgj5lxMF+8us0PXSGPuQFqvCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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