SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d8f5b3cfc1b4ff23e7d7ca9bea313622eb8f6a7937bdc8f1109a369fadabfeb' 
  AND token = 'gTOXcDqcjkufMzDCD20Smcg55v2/MOsz+xIz4B1f11g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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