SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df1ef196d3c068685d3fb0bd093415211143117ed4d39691febc115b4c7c7a9e' 
  AND token = 'ZlvHASz0npSgOJOhTG0QFSgoW68EdsIW30StEDXj9js=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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