SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c3731dd0b7ffe9a936c417e99cbd90d523137f66016c8d3f6ed741ee590cac' 
  AND token = 'Hvkx33rxNRk0BVpJSVKnvH1t5W0Zwa1rq2JzryrhFjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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