SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '13b94558d317bed1233b4719c1fab6a3a4b7f8ba9324f233a696c03a84abc20a' 
  AND token = 'CbXcwSM4SU2KIoZqOTiy/ZbLNi8BcqSL0v0+3Vpzdfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}