SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47e96fc98a7166ff48c54416a67a46e7c47773a72fbe061829f525e0bdc49c3d' 
  AND token = 'Cx+JxxhUyrQOoh9OPmqBmDBwmosmh875sNgte2sXmSs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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