SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a9cf7bd7bd58dbbf6aa71b175f25b73887377dd2fbfaf1a9f1a755e1c4240b6' 
  AND token = 'ZTG2L+jf1uZkIQY9IPpJimHGB6Xil4rgZVCjD4QBxQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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