SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'def92bf36257aa9790484b1aeaa201f58d6ff9cae1277c3700ea3d96617da113' 
  AND token = 'lL2UGLcqlq01kz4qSQdyAmOlRgMOxqZpyjdZJXs1Swc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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