SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ac56307b0e2076e876892113fe55f12e55e00ebac7e75e0b74f58f56cf460d0' 
  AND token = '0AdgURmDUgzrQvR9K3P3HUoAErws64lmbWoku9FYKsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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