SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd2b3afc58f573865f8466c17b86960fb559f9fd4071545a055d63c25f254676' 
  AND token = 'C8XnWquD7JL/gRmHgMKLYLPIC3ZbYrSNV1dHe+gmG5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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