SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54e3ebd966a6847fcb9043d79cb990d569d3b147c5a1099817248afb51436e22' 
  AND token = 'JiRIM2fvTqbKAOgACRSvchdUlwLEAqvfvdGGv2HhgMY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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