SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45a6a7cbc00f79e6b81092e1f85b4fd66414c78003563ffaadb03c6317d55405' 
  AND token = 'UmpO2lS/cg7mS0DJvZw1JpEBhs6/jFNAfO38VKluhyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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